The present invention relates to an engine control apparatus constituted such that, when a lock plate is disengaged from a stop switch knob, the stop switch is turned on to allow an engine of a small motorboat or the like to stop or to be in an idling state.
A small motorboat is made to glide over water while taking a sharp turn or jumping so that an operator can enjoy a ride. This frequently causes the operator to fall into water. Due to this reason, it is required to, when the operator falls into water, stop the engine to prevent only the small motorboat from further progressing. Thus, a small motorboat is generally provided with a stop switch for allowing, when the operator falls into water, the engine to stop or to be in an idling state.
Specifically, a handle bar of the small motorboat is fixed with a switch case. The switch case has a stop switch knob for activating a stop switch of an insertable resin-made lock plate that has at the base end a tightened wire. The tip end of the wire is fixed to the wrist or the like of the operator so that, when the operator falls into water, the lock plate is disengaged from the stop switch knob to turn on the stop switch, thereby allowing the engine of the small motorboat to stop or to be in an idling state.
As described above, the lock plate is inserted to the stop switch knob to allow the engine to start. This causes a situation where, when another lock plate of a small motorboat or a plate member having a similar shape is inserted, a third party can start the engine without the owner's permission. In order to prevent such a situation where a boat is stolen, a conventional technique (as disclosed in Patent reference 1, for example) has suggested that a small motorboat having a control section in which a transponder incorporating an ID code is embedded in a lock plate and inside the switch case an antenna that can receive the ID code so that the engine is controlled based on the received information.
The above conventional engine control apparatus is constituted such that the ID code of the transponder is transmitted via radio transmission to the antenna and the received information is transmitted to the control section so that the engine is started only when a previously registered regular ID code and the received ID code coincide. When the former is different from the latter, the engine is not started. This can start the small motorboat only when the regular lock plate is inserted to the stop switch knob and thus can prevent the boat from being stolen.
[Patent Reference 1]
Japanese Published Unexamined Patent Application No. 2001-88789
However, in the above conventional engine control apparatus, vibration of the engine mounted in the small motorboat always occurs when the engine is driven. This has created a risk in which the vibration is transmitted to the lock plate to cause a defect in the inner transponder. Specifically, the transponder embedded in the lock plate causes the vibration transmitted to the lock plate to be directly transmitted to the transponder.